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& \\
\multicolumn{2}{|c|}{\LARGE\bf THE\hspace*{1cm}STAR\hspace*{1cm}FORMATION\hspace*{1cm}NEWSLETTER} \\ [0.3cm]
\multicolumn{2}{|c|}{\large\em An electronic publication dedicated to early stellar evolution and molecular clouds} \\ [0.3cm]
{\hspace*{0.8cm} No. 99 --- 8 January 2001 } & \multicolumn{1}{r|}{Editor: Bo Reipurth (reipurth@casa.colorado.edu)\hspace*{0.8cm}} \\ [-0.1cm]
& \\ \hline
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%\vspace*{1cm}
%\begin{center}
%{\Large\em From the Editor}
%\end{center}
%\vspace*{0.6cm}
\def\v3{\,{\vspace{0.3cm}}}
\def\v4{\,{\vspace{0.4cm}}}
\def\v5{\,{\vspace{0.5cm}}}
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\begin{center}
{\Large\em Abstracts of recently accepted papers}
\end{center}
\vspace*{0.6cm}
%% Between these brackets you write the title of your paper:
{\large\bf{Molecular Evolution in Collapsing Prestellar Cores}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ Y. Aikawa$^1$, N. Ohashi$^2$, S. Inutsuka$^3$,
E. Herbst$^4$ \& S. Takakuwa$^2$}}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {Department of Earth and Planetary Sciences, Faculty of Science,
Kobe University, Kobe 657-8501, Japan} \\
$^2$ {{Academia Sinica Institute of Astronomy and Astrophysics,
P.O. Box 1-87, Nankang, Taipei 115, Taiwan} \\
$^3$ {National Astronomical Observatory of Japan,
Mitaka, Tokyo 181-8588, Japan}\\
$^4$ {Departments of Physics and Astronomy, The Ohio State
University, Columbus, OH 43210, USA}
%% Here you may write the e-mail address of one or more
%% of the authors who will act as contact person for
%% preprint requests etc., for example:
{E-mail contact: aikawa@jet.planet.sci.kobe-u.ac.jp}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
%% Within the following brackets you place your text:
{We have investigated the evolution and distribution of
molecules in collapsing
prestellar cores via numerical chemical models, adopting the Larson-Penston
solution and its delayed analogues to study collapse.
Molecular abundances and distributions in a collapsing core are
determined by the balance among the dynamical,
chemical and adsorption time scales.
When the central density $n_{\rm H}$ of a prestellar core
with the Larson-Penston flow
rises to $3\times 10^6$ cm$^{-3}$, the
CCS and CO column densities are calculated to show central
holes of radius
7000 AU and 4000 AU, respectively,
while the column density of N$_2$H$^+$ is centrally peaked. These predictions
are consistent with observations of L1544.
If the dynamical time scale of the core is larger than that of
the Larson-Penston solution owing to magnetic fields, rotation,
or turbulence, the column densities of CO and CCS are smaller, and
their holes are larger than in the Larson-Penston core with the same central
gas density. On the other hand, N$_2$H$^+$ and NH$_3$ are more abundant
in the more slowly collapsing core. Therefore, molecular distributions
can probe the collapse time scale of
prestellar cores.
Deuterium fractionation has also been studied via numerical
calculations.
The deuterium fraction in molecules increases as a core evolves and
molecular depletion onto grains proceeds. When the central density
of the core is
$n_{\rm H}= 3\times 10^6$ cm$^{-3}$, the ratio DCO$^+$/HCO$^+$ at the
center is in the range 0.06-0.27, depending on the collapse time scale and
adsorption energy; this range is in reasonable agreement with the observed
value in L1544.
}
% Here you write which journal accepted your paper, for example:
{ Accepted by Ap. J. }
%% If preprints are available on the WWW you can give the web
%% direction here.
http://nova.planet.sci.kobe-u.ac.jp/$\sim$aikawa/paper\_list.html
%\end{document}
\v5
%% Between these brackets you write the title of your paper:
{\large\bf{Linear Analysis of the Hall Effect in Protostellar Disks}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf { Steven A. Balbus$^1$ \ and Caroline Terquem$^{2,3}$ }}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {Virginia Institute of Theoretical Astronomy, Department of Astronomy,
University of Virginia, Charlottesville, VA~22903-0818, USA} \\
$^2$ {Institut d'Astrophysique de Paris, 98~bis Blvd. Arago, 74014 Paris,
France} \\
$^3$ {Universit\'e Denis Diderot--Paris VII, 2 Place Jussieu, 75251 Paris
Cedex 5, France}
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc, for example:
{E-mail contact: sb@virginia.edu, terquem@iap.fr}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
%% Within the following brackets you place your text:
{The effects of Hall electromotive forces (HEMFs) on the linear
stability of protostellar disks are examined. Earlier work on this
topic focused on axial field and perturbation wavenumber geometry.
Here we treat the problem more generally. Both axisymmetric and
nonaxisymmetric cases are treated. Though seldom explicitly included
in calculations, HEMFs appear to be important whenever Ohmic
dissipation is. They allow for the appearance of electron whistler
waves, and since these have right-handed polarization, a helicity
factor is also introduced into the stability problem. This factor is
the product of the components of the angular velocity and magnetic
field along the perturbation wavenumber, and it is destabilizing when
negative. An important finding of our more general calculation is
that unless the field and angular velocity are exactly aligned, it is
always possible to find destabilizing wavenumbers. HEMFs can
destabilize any differential rotation law, even those with angular
velocity increasing outward. Regardless of the sign of the angular
velocity gradient, the maximum growth rate is always given in
magnitude by the local Oort A value of the disk, as in the standard
magnetorotational instability. The role of Hall EMFs may prove
crucial to understanding how turbulence is maintained in the ``low
state'' of eruptive disk systems. }
% Here you write which journal accepted your paper, for example:
{ Accepted by Astrophysical Journal }
%% If preprints are available on the WWW you can give the web
%% direction here.
{Preprint avalaible at http://www.iap.fr/users/terquem/index.html}
\v5
%% Between these brackets you write the title of your paper:
{\large\bf{Constraints on Stirring and Dissipation of MHD Turbulence
in Molecular Clouds }}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ Shantanu Basu$^1$ and Chigurupati Murali$^2$ }}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {Department of Physics and Astronomy, University of Western Ontario,
London, Ontario N6A 3K7, Canada} \\
$^2$ {Department of Astronomy, University of Massachusetts, Amherst,
MA 01003-4525, USA}
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc, for example:
{E-mail contact: basu@astro.uwo.ca}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
%% Within the following brackets you place your text:
{
We discuss constraints on the rates of stirring and dissipation of MHD
turbulence in molecular clouds. Recent MHD simulations suggest that
turbulence in clouds decays rapidly, thus providing a significant
source of energy input, particularly if driven at small scales, by,
for example, bipolar outflows. We quantify the heating rates by combining
the linewidth-size relations, which describe global cloud properties,
with numerically determined dissipation rates. We argue
that, if cloud turbulence is driven on small internal scales, the $^{12}$CO
flux (enhanced by emission from weakly supersonic shocks) will be much larger
than observed; this, in turn, would imply excitation temperatures
significantly above observed values. We reach two conclusions:
(1) small-scale driving by bipolar outflows cannot possibly account
for cloud support and yield long-lived clouds, unless the published MHD
dissipation rates are seriously overestimated; (2) driving on large
scales (comparable to the cloud size) is much more viable from an energetic
standpoint, and if the actual net dissipation rate is only slightly lower than
what current MHD simulations estimate, then the observationally inferred
lifetimes and apparent virial equilibrium of molecular clouds can be
explained.
}
% Here you write which journal accepted your paper, for example:
{ Accepted by ApJ (2001 April 10 issue) }
%% If preprints are available on the WWW you can give the web
%% direction here.
Preprint available at http://www.astro.uwo.ca/$\sim$basu/pub.html
\v5
%% Between these brackets you write the title of your paper:
{\large\bf{Radio Spectral Indices of the Powering Sources of Outflows}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{
Maria T. Beltr\'an$^{1,2}$,
Robert Estalella$^2$,
Guillem Anglada$^3$
Luis F. Rodr\'{\i}guez$^4$
\ and
Jos\'e M. Torrelles$^5$}}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {Harvard-Smithsonian Center for Astrophysics, 60 Garden Street,
Cambridge, MA 02138, USA} \\
$^2$ {Departament d'Astronomia i Meteorologia, Universitat de Barcelona, Av.\
Diagonal 647, E-08028 Barcelona, Spain} \\
$^3$ {Instituto de Astrof\'{\i}sica de Andaluc\'{\i}a, CSIC, Camino Bajo de
Hu\'etor 24, E-18008 Granada, Spain}\\
$^4$ {Instituto de Astronom\'{\i}a, UNAM, Apdo.\ Postal 72-3 (Xangari), 58089
Morelia, Michoac\'an, Mexico}\\
$^5$ {Institut d'Estudis Espacials de Catalunya (IEEC/CSIC) and Instituto de
Ciencias del Espacio (CSIC), Edifici Nexus, Gran Capit\`a 2-4, E-08034
Barcelona, Spain}
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc, for example:
{E-mail contact: mbeltran@cfa.harvard.edu, robert.estalella@am.ub.es}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
%% Within the following brackets you place your text:
{Eight regions containing molecular or HH outflows (Mon~R2E, S287, L1654, L483,
PV~Cephei, L1203, L1251A, and CB~247) have been observed with the VLA at 6~cm,
and a total of 55 sources have been detected above a 5 $\sigma$ level. By
combining our observations at 6~cm with previous data obtained at 3.6~cm, we
estimate the spectral indices of the sources in the fields. For 32 of the
sources we discriminate the sign of the spectral index and thus, we obtain
information about the nature of the emission.
For seven outflows (Mon~R2E, S287-B, L1654, L483, PV~Cephei, L1203, and L1251A)
we found at least a central source with an spectral index consistent with
thermal free-free emission from thermal radio jets.
Multiple sources, separated $\sim10''$, are found near the center of the
Mon~R2E, S287-B, L1654, and L1251A outflows. In the case of S287-B we found two
sources that are valid candidates to drive the S287-B molecular outflow, and
could be related to the outflow excitation.
Under the assumption that the observed emission arises from thermal radio jets,
we discuss the mechanism responsible for the ionization and the constraints
that introduces on their physical parameters, and we estimate
that the flow of ionized material has to originate at a few AU from the
exciting star.
Most of the remaining, non-central, sources are characterized by negative
spectral indices ($\alpha or of order
\def\rbh{R_{\rm BH}}
\def\rroche{R_{\rm tidal}}
%% Within the following brackets you place your text:
{We investigate the physics of gas accretion in young stellar
clusters. Accretion in clusters is a dynamic phenomenon as both the
stars and the gas respond to the same gravitational potential.
Accretion rates are highly non-uniform with stars nearer the centre of
the cluster, where gas densities are higher, accreting more than
others. This competitive accretion naturally results in both
initial mass segregation and a spectrum of stellar masses.
Accretion in gas-dominated clusters is well modelled using a
tidal-lobe radius instead of the commonly used Bondi-Hoyle accretion
radius. This works as both the stellar and gas velocities are under
the influence of the same gravitational potential and are thus
comparable. The low relative velocity that results means that $\rroche
< \rbh$ in these systems. In contrast, when the stars dominate the
potential and are virialised, $\rbh < \rroche$ and Bondi-Hoyle accretion
is a better fit to the accretion rates.}
% Here you write which journal accepted your paper, for example:
{ Accepted by MNRAS }
%% If preprints are available on the WWW you can give the web
%% direction here
http://star-www.st-and.ac.uk/astronomy
%\end{document}
\v5
%% Between these brackets you write the title of your paper:
{\large\bf{Accretion in stellar clusters and the IMF}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ Ian A. Bonnell$^1$, C. J. Clarke$^2$, M. R.
Bate$^2$ and J. E. Pringle$^2$ }}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ School
of Physics and Astronomy, University of St Andrews, North Haugh, St
Andrews, Fife, KY16 9SS, UK \\
$^{2}$ Institute of Astronomy, Madingley
Road, Cambridge CB3 0HA, UK
%% Here you may write the e-mail address of one or more
%% of the authors who will act as contact person for
%% preprint requests etc., for example:
{E-mail contact: iab1@st-andrews.ac.uk}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
\def\simless{\mathbin{\lower 3pt\hbox
{$\rlap{\raise 5pt\hbox{$\char'074$}}\mathchar"7218$}}} % < or of order
\def\simgreat{\mathbin{\lower 3pt\hbox
{$\rlap{\raise 5pt\hbox{$\char'076$}}\mathchar"7218$}}} % > or of order
%% Within the following brackets you place your text:
{We present a simple physical mechanism that can account for the
observed stellar mass spectrum for masses $M_* \simgreat 0.5 M_\odot$.
The model depends solely on the competitive accretion that occurs in
stellar clusters where each star's accretion rate depends on the local
gas density and the square of the accretion radius. In a stellar
cluster, there are two different regimes depending on whether the gas
or the stars dominate the gravitational potential. When the cluster
is dominated by cold gas, the accretion radius is given by a
tidal-lobe radius. This occurs as the cluster collapses towards a
$\rho\propto R^{-2}$ distribution. Accretion in this regime
results in a mass spectrum with an asymptotic limit of $\gamma=-3/2$
(where Salpeter is $\gamma=-2.35$). Once the stars dominate the
potential and are virialised, which occurs first in the cluster core,
the accretion radius is the Bondi-Hoyle radius. The resultant mass
spectrum has an asymptotic limit of $\gamma=-2$ with
slightly steeper slopes ($\gamma\approx-2.5$) if the stars are already mass-segregated.
Simulations of
accretion onto clusters containing 1000 stars show that as expected,
the low-mass stars accumulate the majority of their masses during the
gas dominated phase whereas the high-mass stars accumulate the
majority of their massed during the stellar dominated phase. This
results in a mass spectrum with a relatively shallow $\gamma\approx
3/2$ power-law for low-mass stars and a steeper, power-law for
high-mass stars $ -2.5\simless\gamma\le -2$. This competitive accretion model also
results in a mass segregated cluster.}
% Here you write which journal accepted your paper, for example:
{ Accepted by MNRAS }
%% If preprints are available on the WWW you can give the web
%% direction here.
http://star-www.st-and.ac.uk/astronomy
%\end{document}
\v5
%% Between these brackets you write the title of your paper:
{\large\bf{The CIDA-QUEST Large Scale Survey of Orion OB1:
Evidence for rapid disk dissipation
in a dispersed stellar population}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ C\'esar Brice\~no$^1$, A. Katherina Vivas$^2$, Nuria Calvet$^{3,1}$,
Lee Hartmann$^3$, Ricardo Pacheco$^{1,5}$, David Herrera$^1$, Lysett Romero$^1$,
Perry Berlind$^3$, Gerardo S\'anchez$^1$, Jeffrey A. Snyder$^{4,2}$ \
and Peter Andrews$^4$}}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {Centro de Investigaciones de Astronom{\'\i}a, Apartado Postal 264,
M\'erida 5101-A, Venezuela} \\
$^2$ {Astronomy Department, Yale University, P.O. Box 208101,
New Haven, CT 06520-8101, USA} \\
$^3$ {Smithsonian Astrophysical Observatory, Mail Stop 42,
160 Concord Av., Cambridge, MA 02138, USA} \\
$^4$ {Physics Department, Yale University, P.O. Box 208121,
New Haven, CT 06520-8121, USA} \\
$^5$ {Departamento de F{\'\i}sica, Universidad de los Andes, Conjunto La Hechicera,
Edif. "A", M\'erida 5101, Venezuela}
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc, for example:
{E-mail contact: briceno@cida.ve}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
\def\gtrsim{\mathrel{\hbox{\rlap{\hbox{\lower4pt\hbox{$\sim$}}}\hbox{$>$}}}}
\let\ga=\gtrsim
%% Within the following brackets you place your text:
{
We are conducting a large scale, multiepoch, optical
photometric survey covering $\sim 120$ square degrees
to identify the young low mass stars in the Orion OB1 association.
We present results for a $34 $ square degree area.
Using photometric variability as our main selection criterion,
as well as follow-up spectroscopy,
we have confirmed 168 previously unidentified
pre-main sequence $\sim 0.6 - 0.9 \,$ M$_{odot}$ stars,
with ages $\sim$ 1 - 3 million yr (Ori OB1b) and $\sim$ 3 - 10 million
yr (Ori OB1a). The low mass stars
are spatially coincident with the high mass ($\ga 3$ M$_{odot}$)
members of the associations. Indicators of disk accretion such as
H$\alpha$ emission and near-infrared emission from dusty disks
fall sharply from Ori 1b to Ori 1a, indicating that the time scale for
disk dissipation and
possibly the onset of planet formation is a few million years.
}
% Here you write which journal accepted your paper, for example:
{ Accepted by Science }
%% If preprints are available on the WWW you can give the web
%% direction here.
\v5
%% Between these brackets you write the title of your paper:
{\large\bf{VLA HI Zeeman Observations Toward the W49 Complex}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ C. L. Brogan$^1$, \ and T. H. Troland$^2$ }}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {National Radio Astronomy Observatory, P.O. Box 0, Socorro, NM, 87801,
USA} \\
$^2$ {University of Kentucky, 177 Chem-Phys Bldg, Lexington, KY 40506-0055,
USA}
%% Here you may write the e-mail address of one or more
%% of the authors who will act as contact person for
%% preprint requests etc., for example:
{E-mail contact: cbrogan@aoc.nrao.edu}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
\newcommand\arcsec{``}
\newcommand\HII{H\,{\sc ii}}
\newcommand\HI{H\,{\sc i}}
\newcommand\7{$\sim 7$~km~s$^{-1}$}
\newcommand\4{$\sim 4$~km~s$^{-1}$}
\newcommand\tf{25$\arcsec$}
\newcommand\fo{40$\arcsec$}
\newcommand\ft{15$\arcsec$}
\newcommand\Blos{$B_{los}$}
\newcommand\muG{$\mu$G}
%\newcommand\kms{km~s$^{-1}$}
\newcommand\We{$\mid{\cal W}\mid$}
\newcommand\Te{${\cal T}$}
%% Within the following brackets you place your text:
{We report VLA \HI\/ Zeeman observations toward the W49A star-forming region and
the SNR W49B. Line of sight magnetic fields (\Blos\/) of 60 to 300 \muG\/ at
\tf\/ resolution were detected toward W49A at velocities of \4\/ and \7\/. The
\Blos\/ values measured toward W49A show a significant {\em increase in field
strength with higher resolution} especially for the \4\/ \HI\/ component. The
\HI\/ gas in the velocity range $-5$ to 25 \kms\/ toward W49A shows good
agreement both kinematically and spatially with molecular emission intrinsically
associated with W49A. Based on comparisons with molecular data toward W49A, we
suggest that the \4\/ \HI\/ component is directly associated with the northern
part of the \HII\/ region ring, while the \7\/ \HI\/ component seems to
originate in a lower density halo surrounding W49A. We estimate that the W49A
North core is significantly subvirial (2\Te\//\We\/$\sim 0.2$), and that the
total kinetic + magnetic energies amount to less than 1/3 of the total W49A
North gravitational energy. These magnetic field results suggest that W49A
North is unstable to overall gravitational collapse in agreement with evidence
that the halo is collapsing onto the W49A North ring of \HII\/ regions.
The majority of the \HI\/ column density toward W49B comes from Sagittarius Arm
clouds along the line of sight at $\sim 40$ \kms\/ and $\sim 60$ \kms\/. No
significant magnetic fields were detected toward W49B. Comparison of the
spectral distribution of \HI\/ gas toward W49A and W49B suggests that evidence
placing W49B 3 kpc closer to the sun (i.e. at 8 kpc) than W49A is quite weak.
Although we cannot place W49B at the same distance as W49A, we find the
morphology of a $\sim 5$ \kms\/ \HI\/ component toward the southern edge of W49B
suggestive of an interaction.}
% Here you write which journal accepted your paper, for example:
{ Accepted by ApJ}
%% If preprints are available on the WWW you can give the web
%% direction here.
http://www.aoc.nrao.edu/~cbrogan/publications.html
%\end{document}
\vspace{0.3cm}
%% Between these brackets you write the title of your paper:
{\large\bf{ Evidence for Residual Material in Accretion Disk Gaps: CO Fundamental
Emission from the T Tauri Spectroscopic Binary DQ Tau }}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ John S. Carr$^1$, Robert D. Mathieu$^2$ \ and Joan R. Najita$^3$ }}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {Naval Research Laboratory, Code 7213, Washington, DC 20375, USA} \\
$^2$ {Dept. of Astronomy, University of Wisconsin, Madison, WI 53706, USA} \\
$^3$ {National Optical Astronomy Observatories, 950 N. Cherry Ave.,
Tucson, AZ 85719, USA}
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc, for example:
{E-mail contact: carr@mriga.nrl.navy.mil}
%% Within the following brackets you place your text:
{ We present the discovery of CO fundamental ro-vibrational emission from the
classical T Tauri spectroscopic binary DQ Tau. The high-resolution infrared
echelle spectra reveal emission lines from both the v=1 and v=2 vibrational
levels with line widths of roughly 70 km s$^{-1}$. The average CO excitation
temperature is approximately 1200 K. We model the spectra as arising from gas
in Keplerian rotation about the center-of-mass of the binary. The disk model
requires gas with an average surface density of 5x$10^{-4}$ g cm$^{-2}$ that extends
outward to 0.5 $\pm$ 0.1 AU and inward to at least 0.1 AU from the center-of-mass.
The radial extent for the emitting gas is close to the predicted size of the gap
in the DQ Tau accretion disk that is expected to be dynamically cleared by the
binary. We interpret these results, and previous modeling of DQ Tau's spectral
energy distribution, as evidence for a small amount ($\approx 10^{-10} M_{\odot}$)
of diffuse material residing within the optically-thin disk gap. Thus dynamical
clearing has not been completely efficient in the DQ Tau binary. We suggest that
the material is associated with a flow from the circumbinary disk which feeds the
ongoing accretion at the stellar surfaces. }
% Here you write which journal accepted your paper, for example:
{ Accepted by Astrophysical Journal}
%% If preprints are available on the WWW you can give the web
%% direction here.
http://xxx.lanl.gov/abs/astro-ph/0101059
\vspace{0.3cm}
%% Between these brackets you write the title of your paper:
{\large\bf{The Deceleration of Giant Herbig-Haro Flows}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ Elisabete M. de Gouveia Dal Pino$^1$ }}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {Instituto Astron\^omico e Geof\'{\i}sico, Universidade
de S\~ao Paulo, Av. Miguel St\'efano, 4200, S\~ao Paulo
04301-904, SP, Brazil}
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc, for example:
{E-mail contact: dalpino@iagusp.usp.br}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
%% Within the following brackets you place your text:
{It has been recently discovered that spatially separated Herbig-Haro objects,
once considered unrelated, are linked
within a chain that may extend for parsecs
in either
direction of the embedded protostar forming a {\it giant Herbig-Haro jet}.
Presently, several dozen of these giant flows have been
detected and the best documented example, the HH~34 system,
shows a systematic velocity
decrease with distance on
either side of the source.
In this paper, we have modeled giant jets by
performing fully three-dimensional simulations of
overdense, radiatively cooling jets modulated
with long-period (P $\sim$ several hundred years)
and large amplitude sinusoidal velocity variability at
injection ($\Delta v \sim$ mean jet flow velocity). Allowing them to
travel over a distance well beyond the source, we have found that
multiple travelling pulses develop and their
velocity indeed falls off smoothly and
systematically with distance. This deceleration is fastest if the jet is
pressure-confined,
in which case the falloff in velocity is roughly consistent with
the observations. The deceleration occurs as momentum is
transferred by gas
expelled sideways from the traveling pulses.
The simulation of a pressure-confined, steady-state jet with similar initial
conditions to those of the pulsed jet
shows that the flow in this case experiences $acceleration$. This result
is thus an additional indication that the primary source of
deceleration in the
giant flows
$cannot$ be attributed to braking of the jet head
against the external medium.}
% Here you write which journal accepted your paper, for example:
{ Accepted by ApJ (vol. 541)}
%% If preprints are available on the WWW you can give the web
%% direction here.
\v5
%% Between these brackets you write the title of your paper:
{\large\bf{The Spatial Distribution of the $\lambda$ Orionis
Pre-Main-Sequence Population}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ Christopher J. Dolan and Robert D. Mathieu }}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
{Department of Astronomy, University of Wisconsin--Madison, 475
North Charter Street, Madison, WI 53706, USA}
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc, for
{E-mail contact: dolan@astro.wisc.edu}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
%% Within the following brackets you place your text:
{The $\lambda$~Ori star-forming region presents a snapshot of a
moderate-mass giant molecular cloud 1--2 Myr after cloud disruption by
OB stars, with the OB stars, the low-mass stellar population, remnant
molecular clouds, and the dispersed gas all still present. We have
used optical photometry and multi-object spectroscopy for lithium
absorption to identify 266 PMS stars in 8 degrees$^2$ of the
region. We also present new Str\"omgren photometry for the massive
stars, from which we derive a distance of 450 pc and a turnoff age of
6--7 Myr. Using these parameters and pre-main-sequence evolutionary
models, we map the star-formation history of the low-mass stars. We
find that low-mass star formation started throughout the region at
about the same time as the birth of the massive stars, and thereafter
the birth rate accelerated. Within the last 1--2 Myr star-formation
ceased in the center of the star-forming region, near the
concentration of OB stars, while it continues in dark clouds 20 pc
away. We suggest that a supernova 1--2 Myr ago destroyed the molecular
cloud core from which the OB stars formed, but did not terminate star
formation in more distant reaches of the giant molecular cloud. We
find no secure evidence for triggered or sequential star formation in
the outer molecular clouds. The global star formation of the
$\lambda$~Ori region has generated the field IMF, but local star
formation in sub-regions shows large deviations from the expected
ratio of high- to low-mass stars.}
% Here you write which journal accepted your paper, for example:
{ Accepted by Astron. J. }
%% If preprints are available on the WWW you can give the web
%% direction here.
{http://www.astro.wisc.edu/$\sim$dolan/thesis/}
\v5
%% Between these brackets you write the title of your paper:
{\large\bf{Laboratory and astrophysical detection of the hyperfine structure
of the $J=1-0$ rotational transition of HC$^{17}$O$^+$}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ L. Dore$^1$, G. Cazzoli$^1$ \ and P. Caselli$^3$ }}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {Dipartimento di Chimica "G. Ciamician", Universit\`{a} di
Bologna, via Selmi 2, I-40126 Bologna, Italy} \\
$^2$ {Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5,
I-50125 Firenze, Italy}
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc, for example:
{E-mail contact: dore@ciam.unibo.it}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
%% Within the following brackets you place your text:
{The three hyperfine components of the $J=1\leftarrow 0$
rotational transition of ${\rm HC^{17}O}^+$\, have been resolved
in laboratory leading to a value of the quadrupole coupling
constant $eQq$ of 4.595 MHz, which is far below the previous
estimate of an upper limit of 12 MHz by Gu\'elin et
al. (1982). The ${\rm HC^{17}O}^+$ (1--0) spectrum has been
observed toward the ``molecular peak'' of L1544 and analyzed on
the basis of the laboratory hyperfine frequencies.}
% Here you write which journal accepted your paper, for example:
{ Accepted by A\&A }
%% If preprints are available on the WWW you can give the web
%% direction here.
http://www.arcetri.astro.it/$\sim$starform/publ2000.htm
\clearpage
%% Between these brackets you write the title of your paper:
{\large\bf{Fractal Structure in Galactic Star Fields}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ Bruce G.~Elmegreen$^1$, and Debra Meloy Elmegreen$^2$ }}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {IBM Research Division, T.J. Watson Research Center, P.O. Box 218,
Yorktown Heights, NY 10598, USA} \\
$^2$ {Department of Physics and Astronomy, Vassar College,
Poughkeepsie, NY 12604, USA}
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc, for example:
{E-mail contact: bge@watson.ibm.com}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
%% Within the following brackets you place your text:
{
The fractal structure of star formation on large scales
in disk galaxies is studied using the size distribution function of
stellar aggregates in kpc-scale star fields. Achival HST images of 10
galaxies are Gaussian smoothed to define the aggregates, and a count of
these aggregates versus smoothing scale gives the fractal dimension.
Fractal and Poisson models confirm the procedure. The fractal dimension
of star formation in all of the galaxies is $\sim2.3$. This is the same
as the fractal dimension of interstellar gas in the Milky Way and nearby
galaxies, suggesting that star formation is a passive tracer of gas
structure defined by self-gravity and turbulence. Dense clusters like
the Pleiades form at the bottom of the hierarchy of structures, where
the protostellar gas is densest. If most stars form in such clusters,
then the fractal arises from the spatial distribution of their
positions, giving dispersed star fields from continuous cluster
disruption. Dense clusters should have an upper mass limit that
increases with pressure, from $\sim10^3$ M$_\odot$ in regions like the
Solar neighborhood to $\sim10^6$ M$_\odot$ in starbursts.
}
% Here you write which journal accepted your paper, for example:
{ Accepted by Astron. J. March 2001, Vol 121 }
%% If preprints are available on the WWW you can give the web
%% direction here.
\v5
%% Between these brackets you write the title of your paper:
{\large\bf{Molecular Carbon Chains and Rings in TMC-1}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ David Foss{\'e}$^{1,2}$, Jos{\'e} Cernicharo$^1$, Maryvonne Gerin$^2$,
and Pierre Cox$^3$ }}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {Depto F\'{\i}sica Molecular, I.E.M., C.S.I.C.,
Serrano 121, E-28006 Madrid, Spain} \\
$^2$ {L.R.A., Observatoire de Paris \& Ecole Normale Sup{\'e}rieure, 24
rue Lhomond, F-75231 Paris Cedex 05, France} \\
$^3$ {I.A.S., Universit{\'e} Paris-Sud, b{\^a}timent 121,
F-91405 Orsay, France}
%% Here you may write the e-mail address of one or more
%% of the authors who will act as contact person for
%% preprint requests etc., for example:
{E-mail contact: David.Fosse@lra.ens.fr}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
\newcommand{\lCCCHH} {{\it l}-C$_{3}$H$_{2}$}
\newcommand{\cCCCHH} {{\it c}-C$_{3}$H$_{2}$}
\newcommand{\ccchh} {C$_{3}$H$_{2}$}
\newcommand{\lCCCH} {{\it l}-C$_{3}$H}
\newcommand{\cCCCH} {{\it c}-C$_{3}$H}
\newcommand{\ccch} {C$_{3}$H}
%% Within the following brackets you place your text:
{We present mapping results in several rotational transitions of
HC$_{3}$N, C$_{6}$H, both cyclic and linear C$_{3}$H$_{2}$ and C$_{3}$H,
towards the cyanopolyyne peak of the filamentary dense cloud
TMC-1 using the
IRAM 30m and MPIfR 100m telescopes.
The spatial distribution of the cumulene carbon chain
propadienylidene H$_2$CCC (hereafter \lCCCHH\,) is found to deviate
significantly from the distributions of
the cyclic isomer {\it c}-C$_{3}$H$_{2}$, HC$_{3}$N, and C$_{6}$H which in
turn look very
similar. The cyclic over linear abundance ratio of C$_3$H$_2$
increases by a factor of 3 across the filament, with a value of 28
at the cyanopolyyne peak.
This abundance ratio is an order of magnitude larger
than the range (3 to 5)
we observed in the diffuse interstellar medium.
The cyclic over linear
abundance ratio of C$_3$H also varies by $\sim$ 2.5 in
TMC-1, reaching a maximum value (13) close to the cyanopolyyne peak.
These behaviors
might be related to
competitive processes between ion-neutral and
neutral-neutral reactions for cyclic and linear species.}
% Here you write which journal accepted your paper, for example:
{ Accepted by ApJ }
%% If preprints are available on the WWW you can give the web
%% direction here.
http://arXiv.org/archive/astro-ph
%\end{document}
\v5
%% Between these brackets you write the title of your paper:
{\large\bf{Disks and outflows around intermediate-mass
stars and protostars}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{
A. Fuente$^1$, R. Neri$^2$, J. Mart\'\i n-Pintado$^1$,
R. Bachiller$^1$, A. Rodr\'\i guez-Franco$^1$, F. Palla$^3$ }}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {Observatorio Astron\'omico Nacional (IGN), Campus
Universitario, Apdo. 1143, E-28800 Alcal\'a de Henares (Madrid),Spain}\\
$^2$ {Institut de Radioastronomie Millim\'etrique (IRAM), 300 rue de
la Piscine, Domaine Universitaire, F-38406 St Martin d'H\`eres Cedex,
France}\\
$^3$ {Osservatorio Astrofisico di Arcetri, Largo Enrico Fermi,5
I-50125 Firenze, Italy}
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc, for example:
{E-mail contact: fuente@oan.es}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
%% Within the following brackets you place your text:
{In order to study the existence and evolution of circumstellar disks
around intermediate-mass stars (M$_*$ $\geq$ 3 M$_\odot$),
we have obtained single-dish and interferometric continuum images
at 2.6mm and 1.3mm of the intermediate-mass protostar
NGC 7129 FIRS 2
and of the Herbig Be stars LkH$\alpha$ 234 and HD 200775.
These objects are representative of the different stages of the
pre-main sequence evolution with ages ranging from a few 10$^3$
to 8 $\times$ 10$^6$ years.
Single-dish and interferometric observations of
the outflows associated with these sources are also presented.
In NGC 7129 FIRS 2, two millimeter sources are required
to fit the interferometric 1.3mm continuum emission.
Only the most intense of these millimeter objects, FIRS 2 - MM1,
seems to be associated with the CO outflow. The second and weaker
source, FIRS 2 - MM2, does not present any sign of stellar activity.
The single-dish map of the CO outflow
presents an unusual morphology with the blue and red lobes separated
by an angle of 82$\deg$. The CO J=1$\rightarrow$0 interferometric
image shows that this unusual morphology is the result of the superposition
of two outflows, one of them associated with FIRS 2 - MM1 (the blue lobe in
the single-dish map) and the other (the red lobe) with a new
infrared source (FIRS 2 - IR) which is not detected in the
millimeter continuum images.
The interferometric 1.3mm continuum image of NGC 7129 FIRS 1
reveals that LkH$\alpha$ 234 is a member of a cluster of
embedded objects. Two millimeter clumps
are detected in this far-infrared source. The strongest
is spatially coincident with the mid-infrared companion of
LkH $\alpha$ 234, IRS 6.
A new millimeter clump, FIRS 1 - MM1,
is detected at an offset (-3.23$''$, 3.0$''$)
from LkH$\alpha$ 234.
We have not detected any compact
source towards LkH$\alpha$ 234 with a limit for the mass of a
circumstellar disk, M$_D$ $$50 ks; many are only detected in one of the observations.
The main objective of this paper is to study the Orion Trapezium and
its close vicinity. All five Trapezium stars are bright in X-rays,
with $\theta^1$ Ori C accounting for about 60$\%$ of the total
luminosity of the Trapezium. The CCD spectra of the three very early
type members can be fit with a two-temperature thermal spectrum with a
soft component of kT $\sim$ 0.8 keV and a hard component of kT $\sim$
2 to 3 keV. $\theta^1$ Ori B is an order of magnitude fainter than
$\theta^1$ Ori E and shows only a hard spectrum of kT $\sim$ 3 keV.
$\theta^1$ Ori D is another order of magnitude fainter than $\theta^1$
Ori B, with only a kT $\sim$ 0.7 keV component. We discuss these
results in the context of stellar wind models.
We detect eight additional, mostly variable X-ray sources in the close
vicinity of the Trapezium. They are identified with thermal and
non-thermal radio sources, as well as infrared and optical stars. Five
of these X-rays sources are identified with proplyds and we argue that
the X-ray emission originates from class I, II and III protostars at
the cores of the proplyds.}
{ Accepted by the Astrophysical Journal}
{preprint on: http://space.mit.edu/~nss/orion/orion.html}
%\end{document}
\v5
%% Between these brackets you write the title of your paper:
{\large\bf{Free floating planets in stellar clusters?}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ Kester W. Smith$^{1,2}$ \& Ian A. Bonnell$^3$ }}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {Institute of Astronomy, ETHZ, Z\"urich CH-8092, Switzerland.} \\
$^2$ {Paul Scherrer Institut, CH-5232 PSI-Villigen, Switzerland.} \\
$^3$ {School of Physics and Astronomy, University of St Andrews,
North Haugh, St Andrews, Fife, KY16 9SS, Scotland}
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc, for example:
{E-mail contact: kester@astro.phys.ethz.ch}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
%% Within the following brackets you place your text:
{ We have simulated encounters between planetary systems and single
stars in various clustered environments. This allows us to estimate
the fraction of systems liberated, the velocity distribution of the
liberated planets, and the separation and eccentricity distributions
of the surviving bound systems. Our results indicate that, for an
initial distribution of orbits that is flat in log space and extends
out to 50AU, 50\% of the available planets can be liberated in a
globular cluster, 25\% in an open cluster, and less than 10\% in a
young cluster. These fractions are reduced to 25\%, 12\% and 2\% if
the initial population extends only to 20AU. Furthermore, these
free-floating planets can be retained for longer than a crossing time
only in a massive globular cluster. It is therefore difficult to see
how planets, which by definition form in a disc around a young star,
could be subsequently liberated to form a significant population of
free floating substellar objects in a cluster.}
% Here you write which journal accepted your paper, for example:
{ To appear in MNRAS }
%% If preprints are available on the WWW you can give the web
%% direction here.
{Available at http://www.astro.phys.ethz.ch/papers/smith/smith\_p\_m.html }
\v5
%% Between these brackets you write the title of your paper:
{\large\bf{The Abundance and Emission of H$_2$O and O$_2$ in Clumpy Molecular clouds}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ Marco Spaans$^1$ and Ewine F.\ van Dishoeck$^2$ }}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {Kapteyn Institute, P.O. Box 800, 9700 AV Groningen, The Netherlands} \\
$^2$ {Leiden Observatory, P.O. Box 9513, 2300 RA Leiden, The Netherlands}
%% Here you may write the e-mail address of one or more
%% of the authors who will act as contact person for
%% preprint requests etc., for example:
{E-mail contact: spaans@astro.rug.nl}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
%% Within the following brackets you place your text:
{Recent observations with the {\it Submillimeter Wave Astronomy
Satellite} indicate abundances of gaseous H$_2$O and O$_2$ in
dense molecular clouds which are significantly lower than found in
standard homogeneous chemistry models. We present here results for
the thermal and
chemical balance of inhomogeneous molecular clouds
exposed to ultraviolet radiation in which the abundances of H$_2$O and
O$_2$ are computed for various density distributions, radiation field
strengths and geometries. It is found that an inhomogeneous density
distribution lowers the column densities of H$_2$O and O$_2$ compared
to the homogeneous case by more than an order of
magnitude at the same $A_{\rm V}$. O$_2$ is particularly sensitive to the
penetrating ultraviolet radiation, more so than H$_2$O.
The S~140 and $\rho$ Oph clouds are studied as
relevant test cases of star-forming and quiescent regions. The SWAS
results of S~140 can be accommodated naturally in a clumpy model with
mean density of $2\times 10^3$ cm$^{-3}$ and enhancement $I_{\rm
UV}=140$ compared with the average interstellar radiation field,
in agreement with
observations of [C I] and $^{(13)}$CO of this cloud. Additional radiative
transfer computations suggest that this diffuse H$_2$O component is warm,
$\sim 60-90$ K, and can account
for the bulk of the $1_{10}-1_{01}$ line emission observed by SWAS.
The $\rho$~Oph model
yields consistent O$_2$ abundances but too much H$_2$O, even for
[C]/[O]=0.94, if $I_{\rm UV}<10$ respectively $<40$ for a mean density
of $10^3$ respectively $10^4$ cm$^{-3}$. It is concluded that enhanced
photodissociation in clumpy regions can explain the low
H$_2$O and O$_2$ abundances and emissivities found in the large SWAS beam
for extended molecular clouds, but that additional freeze-out of oxygen
onto grains is needed in dense cold cores.}
% Here you write which journal accepted your paper, for example:
{ Accepted by ApJ Letters }
%% If preprints are available on the WWW you can give the web
%% direction here.
%\end{document}
\v5
%% Between these brackets you write the title of your paper:
{\large\bf{Physical conditions and current massive star formation
in NGC~3603}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ Mauricio Tapia$^1$,
Joaqu{\'\i}n Bohigas$^1$ ,
Brenda P\'erez$^1$ ,
Miguel Roth$^2$ and
Mar{\'\i}a Teresa Ruiz$^3$}}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {Instituto de Astronom\'{\i}a, UNAM, Ensenada, Mexico} \\
$^2$ {Las Campanas Observatory, CIW, Chile} \\
$^3$ {Departamento de Astronom{\'\i}a, Universidad de Chile, Santiago, Chile}
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc, for
{E-mail contact: mt@astrosen.unam.mx}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
%% Within the following brackets you place your text:
{New optical and near-infrared observations of the Galactic HII region
NGC~3603 have been obtained in order to explore the interaction of the
central starburst cluster HD~97950 with the remains of the molecular
cloud and the formation of new generations of OB-type stars. Ample
evidence for continuous stellar formation activity proceeding from
north to south over the past three to six million years is
presented. {\it K}-band excess is found in 50 objects, most of which
are optically very faint ($V>18$) and are the youngest OB-type stars
in the region. Nearly 80$\%$ is clustered or associated to signposts
of recent star formation. Several sources are found near the tips of
the ionization fronts produced by HD~97950. Some of these are young OB
stars which have water masers in their vicinity and, in three cases,
associated to isolated radio-continuum emission peaks. Near the centre
of the active star formation region that is further away from
HD~97950, the Irs 9 cluster, 12 OB-type stars (out of 16) with large
excess emission beyond 2 $\mu$m are found within a 15\arcsec~
radius. The most massive star of this new stellar generation in
NGC~3603 is an O5 - O6 star. An ionization front lies just south of
this very young cluster. }
% Here you write which journal accepted your paper, for example:
{ Accepted by Revista Mexicana de Astronom{\'\i}a y Astrof{\'\i}sica,
Vol. 37 (April 2001)}
%% If preprints are available on the WWW you can give the web
%% direction here.
Preprints available at
http://bufadora.astrosen.unam.mx/~mt/preprints/n360300.ps
\v5
%% Between these brackets you write the title of your paper:
{\large\bf{ The Arcetri Catalog of H$_2$O maser sources: Update 2000}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf R. Valdettaro$^1$, F. Palla$^1$, J. Brand$^2$,
R. Cesaroni$^1$, G. Comoretto$^1$, S. Di Franco$^3$,
M. Felli$^1$, E. Natale$^4$, F. Palagi$^4$, D. Panella$^1$,
G. Tofani$^1$ }
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, I-50125
Firenze, Italy } \\
$^2$ {Istituto di Radioastronomia CNR, Via Gobetti 101, I-40129 Bologna,
Italy } \\
$^3$ { Dipartimento di Astronomia e Scienza dello Spazio,
Largo E. Fermi 5, I-50125 Firenze, Italy } \\
$^4$ { CAISMI, C.N.R., Largo E. Fermi 5, I-50125 Firenze, Italy }
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc, for example:
{E-mail contact: rv@arcetri.astro.it}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
%% Within the following brackets you place your text:
{
We present a second update of the Arcetri Catalog of water masers
(Comoretto et al., 1990; Brand et al. 1994).
The present study reports the results of the observations carried out with
the Medicina 32-m radiotelescope from January 1993 to April 2000 on a sample
of 300 sources. This compilation consists of newly discovered maser sources
that did not appear in the previous Arcetri Catalogs and is made of: a)
detections from the literature, and b) unpublished detections obtained with
the Medicina antenna. Overall, 83 out of 300 sources were detected. The
detection rate is low (28\%) and we attribute this result to the inclusion
in our survey of a rather large number of spurious maser detections that
have appeared in one particular paper. The
observational parameters are reported in tabular form for all the 300
sources and the spectra of the detected masers are presented.
We discuss the global properties of the complete Arcetri Catalog based on
Comoretto et al. (1990), Brand et al. (1994) and the present observations,
which now contains 1013 galactic water maser sources. Of these, 937 have an
IRAS counterpart within 1 arcminute from the nominal position of the maser.
We establish a classification scheme based on the IRAS flux densities which
allows to distinguish between water masers associated with star forming
regions and late-type stars. The Arcetri Catalog represents a useful data
base for systematic studies of galactic water maser sources.
% Here you write which journal accepted your paper, for example:
{ Accepted by Astron. \& Astroph. Supp. }
%% If preprints are available on the WWW you can give the web
%% direction here.
\v5
%% Between these brackets you write the title of your paper:
{\large\bf{Herbig-Haro Objects HH 434-436: Part of a Giant Flow Driven
by the Central Source A/B of IRAS 04325+2402?}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ Hongchi Wang$^{1,2}$, Ji Yang$^{1,2}$, Min Wang$^{1,2}$, Licai
Deng$^{2,3,4}$, Jun Yan$^{1,2}$, and Jiansheng Chen$^{2,3,4}$}}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {Purple Mountain Observatory, Academia Sinica, Nanjing 210008, PR
China} \\
$^2$ {Chinese National Astronomical Observatories, Chinese Academy of
Sciences, A20 Datun Road, Chaoyang District, Beijing 100012, PR China}
\\
$^3$ {Beijing Astronomical Observatory, Chinese Academy of Sciences,
Beijing 100012, PR China}\\
$^4$ {BAC: Chinese Academy of Sciences-Peking University Joint Beijing
Astrophysical Center}
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc, for
{E-mail contact: hcwang@pmo.ac.cn}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
%% Within the following brackets you place your text:
{While carrying out a wide-field survey of nearby star forming regions
for Herbig-Haro (HH) objects we discovered 3 Herbig-Haro objects, HH
434-436, in a $\sim$ 2$^\prime$ $\times$ 2$^\prime$ (0.08 $\times$ 0.08
pc) region near L1536. HH 434 consists of 3 knots. HH 435 shows a bow
shock shape and HH 436 is an elongated patch. Spectroscopic observations
indicate that the excitation levels of HH 434-436 are different: HH 436
has a high excitation level while 434A has an intermediate and 435 has a
low excitation level. The overall morphology of HH 434-436 shows a bow
shock shape and suggests that HH 434-436 may be a single bow shock
fragmented into separate knots. Near infrared observations of the region
in the JHK$^\prime$ broad bands and H$_2$ {\it v} = 1-0 S(1) narrow band
were also carried out but no embedded source was detected. The overall
bow shock of HH 434-436 points back towards an embedded multiple system
IRAS 04325+2402. Moreover, from HST/NICMOS observations HH 434-436 are
located on the expected outflow axis of the central source A/B of this
multiple system. On the basis of these facts we propose that HH 434-436
may be driven by the central source A/B of IRAS 04325+2402, therefore,
they are probably part of a giant HH flow which has a scale of 2.4 pc,
although the possibility that HH 434-436 are three distinct flows can
not be completely ruled out.}
% Here you write which journal accepted your paper, for example:
{ Accepted by Astron. J. }
%% If preprints are available on the WWW you can give the web
%% direction here.
Preprint available at http://jets.pmo.ac.cn/starfm/preprints.html
\newpage
\begin{center}
{\Large\em Dissertation Abstracts}
\end{center}
\begin{center}
% Between these brackets you write the title of your thesis:
{\Large\bf{The Young Population of the Lambda Orionis Star-Forming
Region}}
\vspace*{0.5cm}
% Here comes your name
{\bf{ Christopher Jon Dolan }}
% Here you write the institute where your thesis work was conducted,
{Thesis work conducted at: University of Wisconsin--Madison, USA}
% Here comes your present postal address (if you are about to move and
% your coming address give it as well) e.g.:
{Current address: Department of Astronomy, University of
Wisconsin--Madison, 475 North Charter Street, Madison, WI 53706}
% (if you use this part, remove %%)
% {Address as of XX XXX 1994: }
% Here comes your e-mail address:
{Electronic mail: dolan@astro.wisc.edu}
% Name of your adviser:
{Ph.D dissertation directed by: Robert D.\ Mathieu}
% Month and Year of thesis:
{Ph.D degree awarded: August 2000}
\vspace*{0.8cm}
\end{center}
% Within the following brackets you place your text:
{
To investigate the effect that massive stars have on low-mass star
formation, we have conducted a detailed study of the young stellar
population of the $\lambda$~Orionis star-forming complex. To do this,
we first surveyed the complex to enumerate the young stellar
population, including both high- and low-mass stars. Measuring the
ages and masses of these stars by photometric comparison with stellar
evolution models, we have reconstructed the star-formation history and
initial mass function of the region.
The stellar ages demonstrate that the current episode of star
formation started gradually about 8--10 Myr ago, showing no signs of
triggered or sequential star formation. The birth rate increased
continuously until 1 Myr ago when a supernova exploded, cleared away
the gas from which stars were forming in the center of the
star-forming region. This terminated low-mass star formation within
15 pc of the massive stars while further away stars continue to form
today.
Globally, the mass function resembles that of the field but it shows
substantial local variation across the star-forming region, favoring
massive stars in the center and low-mass stars elsewhere. However, we
do not see strictly bimodal star formation, as the low-mass stellar
density is highest in the same location as the OB stars.
We have discovered a marked lack of accretion disks (diagnosed by
stellar H$\alpha$ emission) around the low-mass stars in the vicinity
of the massive stars. We suspect that close encounters with OB stars
or the supernova shock diminished the disks of those stars. Since the
stars with or without accretion disks span all ages, we conclude that
the absence of disks is the product of environment, not just
evolution.
Thus we find that the star-forming environment near OB stars is
detrimental to further formation. The massive stars may disperse the
gas from which stars form and they may destroy the disks by which
low-mass stars accrete that gas. Nonetheless, low-mass stars do form
in great numbers both near to and far from their massive neighbors.
%% Copy and paste this one:
% http://www.astro.wisc.edu/~dolan/thesis/
http://www.astro.wisc.edu/$\sim$dolan/thesis/
}
\clearpage
\begin{center}
%% Between these brackets you write the title of your thesis:
{\Large\bf{Evidence for the Growth of Dust Grains around Protostars}}
\vspace*{0.5cm}
%% Here comes your name
{\bf{Tracy L. Huard}}
%% Here you write the institute where your thesis work was conducted, e.g.:
{Thesis work conducted at: Vanderbilt University, Nashville, TN, USA}
%% Here comes your present postal address (if you are about to move and know
%% your coming address give it as well) e.g.:
{Current address: Center for Astrophysics, 60 Garden St., Cambridge, MA 02138}
%% (if you use this part, remove %%)
%% {Address as of XX XXX 1994: }
%% Here comes your e-mail address:
{Electronic mail: thuard@cfa.harvard.edu}
%% Name of your adviser:
{Ph.D dissertation directed by: David A. Weintraub}
%% Month and Year of thesis:
{Ph.D degree awarded: December 2000}
\vspace*{0.8cm}
\end{center}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
\def\micron{$\mu$m}
\def\ltsim{\raisebox{-.4ex}{$\stackrel{}{\sim}$}}
\def\arcsec{$^{\prime\prime}$}
\def\arcmin{$^{\prime}$}
%% Within the following brackets you place your text:
{We have mapped the submillimeter emission from protostars that are
forming within small molecular clouds known as Bok globules.
From these maps, which reveal the spatial distribution of thermal dust
emission around the protostars, we have partitioned the total
observed flux into two components: flux from protostellar
dust and flux from dust associated with the molecular cloud.
Assuming that both the protostar and cloud emit as greybodies
with dust opacities given by $\kappa_\nu\,\propto\,\nu^{\beta}$, we have
constrained the values of the ``emissivity index'' $\beta$
using our separate protostellar and cloud
fluxes supplemented with previous flux observations at other
wavelengths. Our analysis of the protostar B\,335\,SMM1, for which
we have the best data, demonstrates that the likely range for the protostellar
dust emissivity index is 0.4\,$\ltsim\,\beta^{\rm p}\,\ltsim$\,1.0, while the
likely range for the cloud dust emissivity index is 1.0\,$\ltsim\,\beta^{\rm
c}\,\ltsim$\,1.8. A similar analysis for two other protostars,
CB\,68\,SMM1 and CB\,230\,SMM1, produce results consistent with
those for B\,335\,SMM1.
We then show that the protostellar dust emissivities are less than and
inconsistent with emissivities predicted by standard models for
interstellar dust grains that include grains only as large as
$\sim$1~\micron. The addition of larger grains is known to yield
smaller emissivities. For this reason, we have constructed a
protostellar dust model with grains composed of a presumed realistic mixture
of constituents: amorphous carbon, silicates, and H$_2$O-ice. We
demonstrate that, for such a protostellar dust population, a
distribution of grain sizes following a power law in grain radius
proportional to $r^{-(3.6\pm0.3)}$ is most consistent with the
protostellar dust emissivities determined in this study.
Furthermore, we show that this protostellar dust population must
include grains at least as large as $\sim$200~\micron, more than
two orders of magnitude larger than standard interstellar
grains.
Since protostars form by collapse of fragments of molecular clouds while
molecular clouds, in turn, form from material within the diffuse
interstellar medium, the observed protostellar dust must once have been
dust associated with molecular clouds. Furthermore, this cloud dust was
originally interstellar dust. Since the typical density of these environments
increases from the diffuse interstellar medium to molecular clouds to
protostars,
dust grain growth may be facilitated by increased probability of coagulation of
the smaller grains. In this scenario, we might expect to see a progression in
the typical grain sizes, from submicron-sized interstellar
grains to intermediate-sized cloud grains to perhaps millimeter-sized
protostellar grains. These millimeter-sized protostellar grains would represent
the seeds from which planetesimals and eventually planets might grow in the
disks
around protostars. Our analysis does not detect any difference
in the sizes of interstellar and cloud dust grains, but this result may be due
to a lack of sensitivity on the part of our method to distinguish these
intermediate grains
from the small interstellar grains. However, the results of our analysis
for the protostars B\,335\,SMM1, CB\,68\,SMM1, and CB\,230\,SMM1, as described
above, indicate that significant grain growth has occurred from interstellar
grains
to the dust grains surrounding these protostars. Given the abundance of
extrasolar planets
that have been detected recently, the findings of this study suggest that
extensive
dust grain growth likely occurs around protostars, in general.
}
%% If you have your thesis on the web, please provide the web address here
%{\url{http://www.hep.vanderbilt.edu/~huard/publications/Huard_PhD.ps.gz}}
{http://www.hep.vanderbilt.edu/~huard/index.html}
\newpage
\begin{center}
{\Large\em New Jobs}
\end{center}
\vspace*{0.6cm}
\centerline{
{\bf\large Three Research Positions in Infrared Astronomy}}
\bigskip
The Infrared Interferometry Group of the Max Planck Institute
for Radioastronomy in Bonn
(see http://www.mpifr-bonn.mpg.de/div/ir-interferometry
invites applications for
{\bf three postdoctoral positions}
in the following fields:
\begin{itemize}
\item Star formation: multiplicity, disks, jets, and outflows of young
stars.
\item Late stages of stellar evolution: stellar surface structure
and circumstellar dust shells (Mira stars, carbon stars, PPN, etc.).
\item Active galactic nuclei: torus, jet, NLR, etc.
\item Infrared long-baseline interferometry with the GI2T, IOTA, and
VLT interferometer.
\end{itemize}
The successful applicants are expected to work primarily on the
observation and interpretation of the above objects. Applicants
should have a Ph.D. and observational or theoretical
experience in one of the above fields. The appointment is initially for
one year, and is renewable for up to five years. Interested scientists
should email a letter of application with a summary of relevant
experience and research interests, a curriculum vitae, a list of
publications, and two letters of recommendation to
\bigskip
Prof. Gerd Weigelt \\
Max Planck Institute for Radioastronomy \\
Auf dem Huegel 69 \\
D-53121 Bonn
Fax: +49 228 525 437 \\
Email: weigelt@mpifr-bonn.mpg.de
\bigskip
Review of applications will begin on 1. Feb. 2001
and continue until the positions are filled.
The Max Planck Society is an equal opportunity employer.
\vspace{1cm}
\clearpage
%% Between these brackets you write the title of your paper:
{\large\bf{The University of New South Wales, Sydney, Australia \\ ~ \\
Department of Astrophysics \\ ~ \\ POSTDOCTORAL RESEARCH FELLOWSHIP \\ ~
\\ in Infrared and Millimetre Astronomy}}
Applications are invited for a Research Associate position funded by
the Australian Research Council, to work with Dr Michael Burton and
Professor John Storey on hot molecular cores in star formation. The
position is for a person with experience in one or more of the
following research areas: (i) infrared astronomy, (ii) millimetre
astronomy, (iii) star formation and (iv) the ISM. Experience in
modelling line emission would also be an asset.
The position will initially be for one year with the possibility of
renewal for a further two years, subject to satisfactory
performance. Candidates must possess a PhD and show a demonstrated
ability to pursue independent research in the relevant fields. The
salary scale for this position will be in the range set by UNSW Academic
Staff Salary Rates (Level A) according to the experience of the successful
applicant.
Further details can be obtained from Dr.\ Burton (email:
M.Burton@unsw.edu.au; tel: +61-2-9385-5618; fax: +61-2-9385-6060; URL:
www.phys.unsw.edu.au/astro.html). Applications should include a CV, a
bibliography and a statement of research interests and plans. They
should be sent to Dr.\ Burton at the School of Physics, University of
New South Wales, Sydney, NSW 2052, Australia before March 1,
2001. Applicants should arrange for up to three letters of
recommendation to arrive at the same address by this date.
The Department of Astrophysics at UNSW is a growing and active group,
consisting of six academics, nine postdoctoral fellows and a dozen
graduate students. We have excellent departmental computing
facilities. Staff members regularly obtain time on national (AAO,
ATNF, ANU 2.3m etc.), international (Gemini, NTT, WHT, UKIRT etc) and
space-based (e.g.\ HST) observing facilities. We also operate the
Automated Patrol Telescope (APT), the Mopra 22-m millimetre-wave
Telescope at Siding Spring Observatory and a site testing observatory
at the South Pole. We are located in Eastern Suburbs of Sydney, the
Olympic city, close to both the city centre and the beaches.
Research activities in the Department include studies of high redshift
galaxies, clusters of galaxies and quasars, cosmology, Antarctic
astronomy, IR and MM astronomy, star formation and the interstellar
medium. There are several major instrumentation projects underway,
including astronomical site-testing and infrared astronomy in
Antarctica, an infrared imaging Fabry-Perot (UNSWIRF), a mid-infrared
camera (MANIAC). We have upgraded the Mopra radio telescope to a 22-m
millimetre-wave telescope, making it the largest such telescope in the
Southern Hemisphere and are developing an automated facility for rapid
monitoring of gamma ray bursts using the Automated Patrol Telescope
(APT).
\clearpage
\begin{center}
{\Large\em New Books}
\end{center}
\vspace*{0.6cm}
\begin{center}
\vspace*{0.4cm}
{\Large\bf New Perspectives on the Interstellar Medium}
{\bf Editors A.R. Taylor, T.L. Landecker, G. Joncas}
\end{center}
The interstellar medium of our Galaxy has multiple components, all of
which cycle from one state to the other through the injection of
energy from stars, addition of mass from stars, and large scale
impacts of spiral shocks. Numerous new results impact our
everchanging view of the processes in the interstellar medium, and
this book, which forms the proceedings of a conference held at
Naramata, British Columbia, Canada in August 1998, gives an up-to-date
overview of our current knowledge.
The following is a partial list of the more extensive papers:
{\bf Part 1. New Observations and Techniques}
{\em Radio Continuum Results from the Canadian Galactic Plane
Survey}~~A.R. Taylor\\
{\em The Canadian Galactic Plane Survey: Atomic
Hydrogen Observations}~~L.A. Higgs\\
{\em The 7C(G) Survey of the Galactic Plane at 151 MHz}~~D.A. Green\\
{\em The Molonglo Galactic Plane Surveys}~~A.J. Green\\
{\em The Molecular Gas Components of the Outer Galaxy}~~M.H. Heyer\\
{\em Polarimetric Investigations of the Galactic Plane at GHz
Frequencies}~~A.R. Duncan\\
{\em High-resolution Mid-Infrared Images of the ISM from the MSX
Satellite}~~M. Cohen\\
{\em Interstellar Dust in the WIRE to PLANCK Era}~~P.G. Martin\\
{\em The AAO/UKST H$\alpha$ Survey}~~Q.A. Parker et al.
{\bf Part 2. Physical States and Phases}
{\em The Gaseous ISM: Observations with the Wisconsion H$\alpha$
Mapper}~~R.J. Reynolds et al.\\
{\em Galactic Cosmic Rays and Magnetic Fields}~~N. Duric\\
{\em Dust Emission and ISM Components}~~F. Boulanger
{\bf Part 3. Processes and Interfaces}
{\em The Eridanus Superbubble in its Multiwavelength Glory}~~C. Heiles et al.\\
{\em Cluster Formation and the ISM}~~R.E. Pudritz \& J.D. Fiege
{\bf Part 4. Disk-Halo Interaction}
{\em Disk-Halo Interactions in External Spiral Galaxies}~~M. Dahlem\\
{\em Observations and Modeling of the Disk-Halo Interaction in Our
Galaxy}~~M. Normandeau \& S. Basu\\
{\em The Interaction of the Disk with the Halo}~~M.-M. Mac Low\\
{\em On the Distribution of Compact, Isolated High-Velocity Clouds
Throughout the Local Group}~~W.B. Burton \& R. Braun
{\bf Part 5. Global Models}
{\em Large-Scale Model of the Interstellar Medium, with New Constraints on
the Hot Gas Component}~~K.M. Ferriere\\
{\em Intersellar Turbulence, Cloud Formation and Pressure
Balance}~~E. V\'azquez-Semadeni
{\bf Part 6. Topology and Structure of the ISM}
{\em The Structure and Statistical Characterisation of HI Gas}~~G. Joncas \&
S. Mashchenko\\
{\em Retrieval of Turbulent Velocity Field Statistics}~M.H. Heyer \&
C. Brunt
{\bf Part 7. Energy Injection}
{\em Mechanisms of Injection and Dissipation of Energy and their Relation
to the Dynamics of the Interstellar Medium}~~A. Pouquet et al.\\
{\em Supershells Formed by Stellar Winds and SNe from OB Associations: On
the Nature of their Two-Component Kinematics}~~T.A. Lozinskaya
\vspace{0.3cm}
ISBN 1-886733-89-9 - published 1999 - 473 pages\\
Price US\$ 52.00 plus postage\\
Order from:
\vspace{0.1cm}
Astronomical Society of the Pacific\\
390 Ashton Avenue\\
San Francisco, CA 94112-1722, USA
Phone: 415-337-1100\\
Fax: 415-337-5205\\
E-mail: catalog@aspsky.org
\vspace{0.8cm}
\begin{center}
\vspace*{0.4cm}
{\Large\bf Stellar Clusters and Associations:\\
Convection, Rotation, and Dynamos}
{\bf Editors R. Pallavicini, G. Micela, S. Sciortino}
\end{center}
This book presents the proceedings of a conference held In Palermo,
Italy on May 25-28, 1999, which was the second of three devoted to the
topic ``Stellar Clusters and Associations: Formation, Structure and
Evolution of Low-Mass Stars''.
The book is divided into the following seven sections:
1. Stellar Structure and Evolution\
2. Cluster Distances and Ages\\
3. IMF, Mass Segregation and Cluster Evolution\\
4. Lithium Abundances and Metallicities\\
5. Rotation and Angular Momentum Evolution\\
6. Magnetic Fields and Stellar Activity\\
7. New Technologies/Large-Scale Programs
Numerous articles in the book has interest for researchers in the star
formation and young star community. Among the reviews with direct
impact on pre-main sequence studies are the following:
{\em Convection and light element evolution from pre-main sequence to
the upper asymptotic giant branch}~~F. D'Antona\\
{\em Cluster IMFs and mass segregation: dynamical effects}~~R. de la
Fuente Marcos\\
{\em Early evolution of stellar clusters}~~I.A. Bonnell\\
{\em Lithium depletion in open clusters}~~R.D. Jeffries\\
{\em Age-dating open clusters with the lithium depletion boundary
test}~~J. Stauffer\\
{\em Examining the case for regulation of pre-main-sequence rotation
by circumstellar disks}~~K.G. Stassun et al\\
{\em Measurements of stellar magnetic fields}~~C.M. Johns-Krull \&
J.A. Valenti
\vspace{0.3cm}
ISBN 1-58381-025-0 - published 2000 - 574 pages\\
Price US\$ 52.00 plus postage\\
Order from:
\vspace{0.1cm}
Astronomical Society of the Pacific\\
390 Ashton Avenue\\
San Francisco, CA 94112-1722, USA
Phone: 415-337-1100\\
Fax: 415-337-5205\\
E-mail: catalog@aspsky.org
\clearpage
\begin{center}
\vspace*{0.4cm}
{\Large\bf New Light on Dark Stars:}\\
{\large\bf Red Dwarfs, Low-Mass Stars, Brown Dwarfs}
{\bf I. Neill Reid and Suzanne L. Hawley}
\end{center}
The low-mass end of the initial mass function has been an extremely
active subject of research within the last few years, and with the
recent discovery of numerous brown dwarfs and very-low-mass stars and
the definition of the new spectral classes of L and T dwarfs, the
topic has moved from the realm of pure theory to an active
observational field. The pioneering book by Kumar opened up the study
of the stellar/substellar mass boundary, and the timely appearance of
this substantial monograph provides a sorely needed update on this
exciting new field. The book gives an overview of our knowledge up to
1999/2000, with extensive references to the literature, at a level
accessible to advanced undergraduate physics majors. It will form an
excellent basis for a graduate course on brown dwarfs and other
low-mass objects. Surely the book will also be frequently used as a
reference book by many researchers in the field.
The book is divided into the following 11 sections:
1. Astronomical Concepts\\
2. Observational Properties of Low-Mass Dwarfs\\
3. The Structure, Formation and Evolution of Low-Mass Stars and Brown Dwarfs\\
4. The Photosphere\\
5. Stellar Activity\\
6. A Galactic Structure Primer\\
7. The Stellar Luminosity Function\\
8. The Mass Function\\
9. Brown Dwarfs\\
10. Extrasolar Planets\\
11. M Dwarfs in the Galactic Halo
\vspace{0.3cm}
ISBN 1-85233-100-3 - published 2000 - 470 pages\\
Price US\$ 146.00 plus postage\\
Order from:
\vspace{0.1cm}
Springer Verlag-New York\\
P.O. Box 19386 Newark, New Jersey 07195-9386, USA\\
Phone: 1-800-springer\\
Fax: 1-201-348-4505\\
E-mail: service@springer-ny.com
\clearpage
\clearpage
\begin{center}
{\Large\em Meetings}
\end{center}
\vspace*{0.6cm}
\begin{center}{\Large\bf %
Deuterium in the Universe
}\end{center}
\begin{center}
June 25-27, 2001 \\
Observatoire de Meudon, France
\end{center}
\vspace*{0.5cm}
{\bf International Scientific Commitee:}
D. Gautier (chair), S. Burles, J. Geiss,
W.M. Irvine, T.J. Millar, T.C. Owen, F. Palla, P. Salati, A. Vidal-Madjar,
E.F. van Dishoeck
\\
{\bf Local organisation Commitee:} E. Roueff (chair), D. Bockelée-Morvan,
L. d'Hendecourt, R. Ferlet, M. Gerin, M. Lemoine, F. Robert, M. Signore
\vspace*{0.5 cm}
\noindent
{\bf THE MEETING:}\\
The study of cosmic Deuterium is a fast expanding research topic of
multidisciplinary nature. Deuterium and deuterated species are observed in a
variety of astrophysical regions, from external galaxies to our own planetary
atmosphere. Formed in the very first moments of the Universe and burned
inside stars, deuterium is also subject to large fractionation effects. It
is thus a powerful tracer of the dominant processes which govern the
evolution of astrophysical objects and media, including the formation of
the Universe up to that of our Solar System.
This 3-days meeting will cover most of topics related to deuterium studies,
addressing the fundamental questions which arise from present observations
and which will be answered by the coming new instrumentations. One day
will be devoted for each of the following topics:\\
\hspace*{3cm} $\bullet$ Solar System \\
\hspace*{3cm} $\bullet$ The interstellar medium and star forming regions\\
\hspace*{3cm} $\bullet$ Nucleosynthesis and cosmology.\\
{\bf WEB SITE OF THE CONFERENCE:}\\
{\tt http://wwwusr.obspm.fr/unicom/deuterium/textes/home.htm}
{\bf E-MAIL ADDRESS:}\\{\tt deuterium.2001@obspm.fr}
\vspace*{0.8cm}
PRE-REGISTRATION BEFORE JANUARY 15, 2001 IS WELCOME !
\clearpage
\begin{center}
{\large \it European Southern Observatory Workshop: Second Announcement}
% \rule{12.2cm}{0.3mm} \\
\vspace{0.5cm}
{\LARGE \sf The Origins of Stars and Planets:
\vspace{0.3cm}
The VLT View}
\vspace{0.5cm}
% \rule{12.2cm}{0.3mm}
%\vspace{-0.3cm}
{\large \sf ESO Auditorium, Garching bei M\"unchen, 24--27 April 2001}
\end{center}
\vspace{5mm}
%
Understanding how stars and planets form in the cold interiors of molecular
clouds presents one of the most formidable challenges of modern astrophysics.
Many important observational clues concerning this fundamental process have
been amassed during the last two decades, almost all associated with major
technological developments. Which scientific breakthroughs can we predict
and plan to achieve with the new generation of 8-metre class telescopes
combined with state-of-the-art instrumentation? This workshop will bring
together the star and planet formation community to discuss the unique
opportunities offered by the ESO Very Large Telescope, comprising the four
8-metre unit telescopes, VLTI, VST, VISTA, and their extensive array of
UV, optical, and infrared instruments. An important goal of the workshop
will be to characterise the needs of the community regarding future VLT
instrumentation. We will also look forward to future complementary facilities
with ESO involvement, in particular ALMA and OWL, and more broadly at
other ground- and space-based observatories with likely important impact
on the study of star and planet formation, including Gemini, Keck, LBT,
HST, Chandra, XMM Newton, SIRTF, FIRST, and the NGST\@.
{\it Topics to be covered:}
\begin{itemize}
\setlength{\itemsep}{-5pt}
\setlength{\parsep}{0pt}
\setlength{\topsep}{-10pt}
\setlength{\partopsep}{0pt}
\item The structure of molecular clouds
\item The physics of star formation: collapse,
accretion, and outflows
\item Chemical processes in star and planet formation
\item Pre-main-sequence stellar evolution
\item Origin and characterisation of the initial mass function
in different environments
\item Evolution of protoplanetary disks and the birth of planets
\item The connection to the extragalactic domain
\end{itemize}
{\it Scientific Organizing Committee:} \\
%
\hspace{0.5cm} J. Alves (co-chair), F. Bertoldi, F. Boulanger, C. Clarke,
C. Cesarsky, E. van Dishoeck, F. Malbet, M. Mayor, R. Genzel, T. Henning,
C. Lada, M. McCaughrean (co-chair), A. Moorwood, A. Natta, F. Paresce,
B. Reipurth, M. Romaniello, \& E. Tolstoy
{\it Local Organizing Committee:} \\
%
\hspace{0.5cm} J. Alves (chair), M. Romaniello, \& C. Stoffer
For more information and registration: {\tt http://www.eso.org/starplanet2001}
\begin{center}
{\bf Closing date for registration is January 31st 2001, but as there are
not many spaces remaining, please register as soon as possible to guarantee
your participation in this meeting.
}
\end{center}
\clearpage
\begin{center}
2nd ANNOUNCEMENT
{\large\bf Submillimeter Astronomy Science Workshop for\\
Far Infrared and Submillimeter Telescope (FIRST)}
{\Large\bf "Herschel/FIRST - A Vision of the Cool Universe"}
\end{center}
A Workshop will be held at Humphrey's Half Moon Inn on Shelter Island, San
Diego, 11th to 13th February, 2001, to help inform the US astronomy
community of the scientific opportunities available with the FIRST mission.
The science workshop will be followed (14th - 16th of February, 2001) by
the annual TeraHertz (THz) Technology Symposium (contact Imran Mehdi at
imran@merlin.jpl.nasa.gov), where relevant technology will be discussed.
Participants will be welcome to attend either or both components. A visit
to Composite Optics Inc. will be arranged between the two meetings.
Registration for the FIRST Science Workshop is required (see below), but is
at no cost.
LIST OF INVITED SPEAKERS\\
M. Fall (STScI) - Theories of Galaxy Formation and Evolution;
C. Steidel (Caltech) - Observations of Distant Galaxies (Optical);
A. Blain (Cambridge) - Observations of Distant Galaxies (Submm);
B. Draine (Princeton) - Physics of the ISM;
E. Herbst (Ohio State) - Chemistry in Star Forming Regions;
E. Lada (U. Florida) - Physics of Star Formation;
J. Fischer (NRL) - CII in Galaxies;
M. Gerin (ENS) - ISO Extragalactic Results;
G. Blake (Caltech) - Line Surveys with FIRST;
N. Scoville (Caltech) - ALMA Science - Extragalactic;
N. Evans (U Texas) - ALMA and Galactic Studies;
P. Solomon (Stony Brook) - Nearby Galaxies;
P. Goldsmith (Cornell) - SWAS Science Results;
G. Pilbratt (ESTEC) - Introduction to FIRST;
A. Poglitsch (MPI, Garching) - Introduction to PACS;
M. Werner (JPL) - Synergy with SIRTF;
J. Davidson (NASA Ames) - SOFIA and FIRST;
D. Neufeld (Johns Hopkins) - ISO Galactic Results;
D. Wilner (CFA) - The SMA and FIRST;
G. Pilbratt (ESTEC) - Introduction to FIRST;
A. Poglitsch (MPI, Garching) - Introduction to PACS;
J. Bock (JPL/Caltech) - Introduction to SPIRE;
M. Harwit (Cornell) - Planck and FIRST;
T. Phillips (Caltech) - Introduction to HIFI.
FIRST Mission "FIRST" is an ESA "Cornerstone Mission" in the Horizon
2000 program, consisting of a passively cooled 3.5m diameter
telescope, operating in the 60-600 micron range at the L2 point.
There are three instruments in the helium cooled focal plane:
SPIRE, a long wavelength (200 - 670 micron) camera and low resolution
spectrometer;
PACS, a short wavelength (60 - 210 micron) camera and low resolution
spectrometer; and
HIFI, a high resolution (heterodyne) spectrometer, operating from 450 -
1900 GHz.
Registration:\\ If you wish to attend, please register electronically.
There is no registration fee planned for this workshop.
Contacts:\\
The organizing committee is T. Phillips (chair), P. Goldsmith, P. Harvey,
M. Harwit, G. Helou, W. Langer, and G. Stringfellow.
Web-page: http://spider.ipac.caltech.edu/staff/lmh/FIRST/workshop.html
Registration forms, and any questions should be sent to
charmaine.d.mayes@jpl.nasa.gov
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{The Star Formation Newsletter is a vehicle for fast distribution of
information of
interest for astronomers working on star formation and molecular
clouds. You can submit material for the following sections: {\em
Abstracts of recently accepted papers} (only for papers sent to refereed
journals, not reviews nor conference notes), {\em Dissertation Abstracts}
(presenting abstracts of new Ph.D dissertations), {\em Meetings}
(announcing meetings broadly of interest to the star formation
and interstellar medium community), {\em New Books} (giving details of
books relevant for the same community), {\em New Jobs} (advertising
jobs specifically aimed towards persons within our specialty), and {\em
Short Announcements} (where you can inform or request information from
the community). \\
{\bf Latex macros for submitting abstracts and dissertation abstracts
are appended to each issue of the newsletter}. \\
The Star Formation Newsletter is available on the World Wide Web at
http://casa.colorado.edu/reipurth or at
http://www.eso.org/gen-fac/pubs/starform/ .
}}}
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{ {\Large\bf Moving ... ??}\\
If you move or your e-mail address changes, please send the editor your
new address. If the Newsletter bounces back from an address for three
consecutive months, the address is deleted from the mailing list.
}}}
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%%% LaTeX MACRO FOR THE STAR FORMATION NEWSLETTER %%%
%%% %%%
%%% Please use for abstracts of papers which have been ACCEPTED in %%%
%%% REFEREED JOURNALS (do not send abstracts of reviews for books %%%
%%% or conference notes). Merely fill in the brackets below and %%%
%%% mail to reipurth@casa.colorado.edu. If you have problems, let %%%
&&& me know in an accompanying note and I will fix them. %%%
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%\begin{document}
%% Between these brackets you write the title of your paper:
{\large\bf{Title of Paper}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ First Author$^1$, Second Author$^2$ \ and Third Author$^3$ }}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {European Southern Observatory, Casilla 19001, Santiago 19, Chile} \\
$^2$ {Cerro Tololo Inter-American Observatory, National Optical Astronomy
Observatories, Casilla 603, La Serena, Chile} \\
$^3$ {Las Campanas Observatory, Carnegie Inst. of Washington, Casilla
601, La Serena, Chile}
%% Here you may write the e-mail address of one or more
%% of the authors who will act as contact person for
%% preprint requests etc., for example:
{E-mail contact: astronomer@star.institute.edu}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
%% Within the following brackets you place your text:
{This is the abstract of your paper.}
% Here you write which journal accepted your paper, for example:
{ Accepted by Astron. J. }
%% If preprints are available on the WWW you can give the web
%% direction here.
%\end{document}
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%%%
%%% LaTeX MACRO FOR DISSERTATION ABSTRACTS
%%%
%%% Please use the following macro for your thesis abstract. You
%%% have one full page for everything, and you are very welcome to
%%% go into detail with your results, so the readers get a
%%% comprehensive overview of your work. Merely fill in the
%%% brackets below and mail to reipurth@casa.colorado.edu
%%%
%%%
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% To process with latex, first remove the % in front of latex commands
%\documentstyle{article}
%\textwidth 18cm
%\textheight 23cm
%\oddsidemargin -1cm
%\topmargin 0cm
%\parskip 0.15cm
%\parindent 0pt
%\small
%\begin{document}
\begin{center}
%% Between these brackets you write the title of your thesis:
{\Large\bf{Title of Thesis}}
\vspace*{0.5cm}
%% Here comes your name
{\bf{ Author }}
%% Here you write the institute where your thesis work was conducted, e.g.:
{Thesis work conducted at: Steward Observatory, University of Arizona, USA}
%% Here comes your present postal address (if you are about to move and know
%% your coming address give it as well) e.g.:
{Current address: European Southern Observatory, Casilla 19001,
Santiago 19, Chile}
%% (if you use this part, remove %%)
%% {Address as of XX XXX 1994: }
%% Here comes your e-mail address:
{Electronic mail: doctor@sun.institute.edu}
%% Name of your adviser:
{Ph.D dissertation directed by: Galileo Galilei}
%% Month and Year of thesis:
{Ph.D degree awarded: Month Year}
\vspace*{0.8cm}
\end{center}
%% Within the following brackets you place your text:
{This is the abstract of your thesis}
%\end{document}